Motor Oil 101 is a joke. Please don't take it as gospel. If you really want to understand oil pumpability,viscosity properties,etc,get in touch with Shannow on that site. The Nissan TSB is actually current. Nissan doesn't want anything below a 10W used in our cars. Maybe my uoa shows why,as you can see how fast the RP 20W50 sheared down to a 40 weight in only 3200 miles.